Modern road surfaces typically comprise asphalt, macadam, concreter, or other bituminous material processed and applied to form a smooth paved surface. Where low quality pavement components are used, or where pavement components are improperly implemented or combined, the paved surface may deteriorate quickly, necessitating frequent maintenance and repair. Even under normal conditions, temperature fluctuations, weather, and vehicular traffic over the paved surface may result in cracks and other surface irregularities over time. Road salts and other corrosive chemicals applied to the paved surface, as well as accumulation of water in surface cracks, may accelerate pavement deterioration. In some cases, concrete roads may shift over time resulting in uneven roads which are often planed to restore a smooth surface.
U.S. Pat. No. 6,439,317 to Minotti, et al., which is herein incorporated by reference for all that it contains, discloses a device for breaking up a paved surface which attaches to a host transport, such as a skid steer or backhoe, having a hydraulic power supply and preferably comprises a closed hydraulic system which includes a regenerative and concentric type double hydraulic cylinder arrangement adjustably supported within a vertical frame. The cylinder is operably attached to a weight such that when fluid is pumped into a first chamber, a piston drives a rod, thereby lifting a weight while at the same time, the piston forces hydraulic fluid from a second chamber to the host. The piston separates the first chamber form the second chamber within the cylinder. Upon reaching a prescribed height, a valve is opened, allowing fluid to flow from the first chamber into the second chamber, thereby allowing the weight to drop rapidly under the influence of gravity. The inventive device for breaking a paved surface includes an adjustment system for adjusting the vertical position of the cylinder within the frame and a system for preventing operation of the device unless it is properly positioned above the surface for breaking.
U.S. Pat. No. 4,767,162 to Reed, III which is herein incorporated by reference for all that it contains, discloses a hydraulic system for a pavement cutting machine that controls the engagement and disengagement of a rotating blade with a pavement surface. A proportional-flow manual-release valve is arranged in series with a pressure-compensated maximum-flow control valve to allow a rapid raising of the blade and an initial relatively rapid lowering of the blade followed by a controllable slower blade descent.